Nutritional products such as infant formula and compositions designed to provide enteral nutritional support to patients in a hospital, other health care settings or, indeed, at home are well known. Some of these products, including infant formula, are designed to provide all necessary nutrients whilst others can also be used as supplements to a normal diet. Of known enteral nutritional compositions, some are directed to specific disease states whilst other products are more generic and broad based for providing nutritional support to patients who cannot obtain necessary nutrients through traditional means of eating food. In general, however, such nutritional products will contain all three macronutrients protein, fat and carbohydrate as well as micronutrients such as vitamins, minerals, trace elements and other components in accordance with the intended use of the composition.
For example, certain populations may require increased protein levels. Likewise, certain populations may require hydrolysed or non intact protein. For example, infants with established cows' milk allergy should only be fed formulas in which the cows' milk proteins have been extensively hydrolysed (for example degree of hydrolysis 28%). Another example of a population where hydrolysed proteins are indicated is patients with impaired gastrointestinal tolerance such as may be associated with conditions such as pancreatitis and short bowel syndrome for example as well as patients resuming enteral feeding after a period of total parenteral nutrition.
Such nutritional products may be supplied as powders for reconstitution with water immediately prior to consumption. Alternatively, they may be supplied in liquid form ready for immediate consumption or administration. A problem that may be encountered when nutritional products are supplied in liquid form is a tendency to phase separation over time. Thus, whilst the manufacturing process results in a homogeneous emulsion, if the product is stored for any length of time before being used, it may start to separate into aqueous and non-aqueous phases and present a “curdled” (volume of clear serum topped by a distinct “creamy” phase) to the consumer or care-giver responsible for administration of the product. In general, this phenomenon does not adversely affect the nutritional quality or efficacy of the product but it may create an adverse impression in the minds of some consumers regarding the product's quality and acceptability.
This problem of phase separation is exacerbated by the use of certain ingredients such as hydrolysed proteins and egg phospholipids as well as by the heat treatments which are necessary to ensure the sterility of the products after manufacturing.
Various stabilisers and stabiliser systems have been proposed to address this problem. For example, in EP 1225809, it is proposed to use a stabiliser system comprising high amylose starch and guar gum.
There is however a continuing need to improve the stability of liquid nutritional compositions, particularly those containing partially hydrolysed protein and fat.